Thanks DP, but my years of experience are not a lot of help in the quad area as it is all so new and so different.
Quads really come under the definition of computer controlled gravity defying machines as against flying machines.
Still where I once knew absolutely nothing about quads, I now know next to nothing about quads.
That is real progress. If I keep it up I will soon know almost nothing.

Evidence that even legends in a field can find someplace to be a n00b again! Very cool.

(13-May-2017, 01:14 PM)Keyboard Kid Wrote: Still where I once knew absolutely nothing about quads, I now know next to nothing about quads.
That is real progress. If I keep it up I will soon know almost nothing.

And that's about the truth of this hobby too! 

Welcome!

(07-May-2017, 08:07 PM)fftunes Wrote: Was wondering too... now, the battery shouldn't sag that much, though it maybe could happen if it went into some sort of "invisible mid-throttle oscillations" ...

On second read... is the FC power supply somewhat protected by low-esr caps or similar? Because electrical noise upsetting the gyro could eat away a lot of power and efficiency.

My friend had this problem once on a new build which didn't deliver half the power it was supposed to have. We could hear a high-frequency hum coming from it, but on your large build w/ large heavy props, something like this might be less noticeable.

PS: Why not make a thread for this in the 350mm etc. folder, the topic is somewhat hidden here while there's probably quite some interest in "heavy lifter" projects.

Hi FFTunes, thanks for the tips. I have wondered about noise and found that the Hero does have filters to eliminate noise but how do you find out what frequency to filter? I do not have a flight log and as a result I am seriously considering swapping the D-shot ESC to my old Hefei KK ESC with data logs which will at least track voltage, current, RPM, temperature and throttle position.

I will also consider moving across to the 350mm thread as you suggested.

Thanks also to the members who have commented on my modelling experience.

Silvertone Electronics have just posted a new and updated story of my antics over the past 50 years.
If anybody is interested you will find it at the following link;
https://www.silvertone.com.au/content/si...ne-story-0

I must say when I read that story at this point in my life I am amazed at how I fitted it all in and that really is only part of the story.

Thanks once again for the help offered by the members of this forum. It is much appreciated believe me.
Regards,
KK

You have to differ between physical noise (this is what the flightcontroller hardware/software filters are for) and electrical noise to which some fc's are very sensitive, if their circuitry is not protected against.

Electrical noise usually comes from escs that have active braking, which is really necessary to properly control modern multirotor's motors. If i were you i'd keep the dshot escs.

Writing from phone, might add more later.

PS: looking forward to your thread, also curious to see some pics of that project of yours.

Thanks FF, now another question. What is TPA and how does it effect the flight performance?

I have just done another load test flight and just barely got 3.93kg off the ground. This is less than 50% of the projected 8.0kg + promised by bench testing.

There must be a control setting in that FC that sets the available total power for normal flight which will allow for extra power for in flight corrections and stunts. Do you know of such a setting?

Howdy Boys,
Just had my longest single flight to date 3:59.
Now I am starting to get a handle on the rules of this game.
When I landed I had 39% battery in reserve.
Yesterday at 4kg I could barely get off the ground and rise above the ground cushion (30cm)  with an AUW of 3.93kg.
Today with the 540g ballast strip removed Wooden It flew very nicely.
Off the ground easily, climb to altitude OK and smooth, reasonably fast controllable descent.
Now my original design parameters were for the completed project, 5.6kg AUW with an estimated 8.3kg thrust giving me a reserve thrust of  2.7kg. Far in excess of what is actually required.
So my new design parameters are 5.8kg AUW with a reserve thrust of 600g giving me an all up thrust of 6.4kg.
That figure is well within reach with either bigger props or more voltage or perhaps even both.
So at last some of the guess work is starting to evaporate and Wooden It is starting to earn its keep.
Not only that it is teaching me to fly. No easy task!
Regards,
KK.

I am trying to locate 13" or 14" spoon type props similar to the APC Slow Fly props in both CW and CCW. APC does not go above 11" from memory. Does anybody know of a source of these types of props?

(16-May-2017, 11:41 PM)Keyboard Kid Wrote: Thanks FF, now another question. What is TPA and how does it effect the flight performance?

I have just done another load test flight and just barely got 3.93kg off the ground. This is less than 50% of the projected 8.0kg + promised by bench testing.

There must be a control setting in that FC that sets the available total power for normal flight which will allow for extra power for in flight corrections and stunts. Do you know of such a setting?

TPA typically only reduces the influence of P and D at higher throttle levels. Say if your quad would start to oscillate at high throttle levels, this would be an easy way to fix.

Kiss FC/firmware has a more elaborate TPA function, it allows to be adjusted as a 3-dot curve over the whole throttle range. But again, it's typically only used for high/full throttle scenarios.

I don't know that fc/firmware you're using. I can speak for cleanflight/betaflight though which basically does not make a difference between normal flight and full throttle - if at full throttle a correction or a high rotation rate is requested and motors can't go higher to do so, they simply lower output of the other motors to achieve the same effect. There is no power reserved.

EDIT; but this made me think of another possible cause for a lack of power - if only one esc or motor is weaker (for whatever reason - shorted windings, bad magnets or components), then the rest of the motors will be held back by the flight controller in order to keep control.

fftunes
TPA typically only reduces the influence of P and D at higher throttle levels. Say if your quad would start to oscillate at high throttle levels, this would be an easy way to fix.

Kiss FC/firmware has a more elaborate TPA function, it allows to be adjusted as a 3-dot curve over the whole throttle range. But again, it's typically only used for high/full throttle scenarios.

I don't know that fc/firmware you're using. I can speak for cleanflight/betaflight though which basically does not make a difference between normal flight and full throttle - if at full throttle a correction or a high rotation rate is requested and motors can't go higher to do so, they simply lower output of the other motors to achieve the same effect. There is no power reserved.

EDIT; but this made me think of another possible cause for a lack of power - if only one esc or motor is weaker (for whatever reason - shorted windings, bad magnets or components), then the rest of the motors will be held back by the flight controller in order to keep control.

Thanks FF. Re the motors, I tested all four and there was only a 0.3kg difference in thrust over the whole four motors with the variation being 2.0 - 2.3 kg using 12 x 6 SF props.. Even allowing for less efficient props, 1.6kg was a typical thrust value. That is still in excess of 6kg  so what on earth is happening? It is possible that the bumping around I gave it in the early stages did damage a motor and it is here that I miss the Hefei KK ESC. That data log is so valuable.

Re the TPA, there is no problem at full throttle. The quad is very smooth with no oscillation or snap-back what so ever. Nor do the motors get any hotter than barely warm at the end of a 4 minute flight. The batteries are mildly warm.

Re the FC. It is a Hero and I use Betaflight to tune the PIDs etc.

So I will keep working, flying and asking questions until I come up with a satisfactory solution which allows me to press on to the next stage of the project.

I will say this, buying 4 of everything every time you change something soon gets horribly expensive. Especially working with the big motors, props etc.

BTW, please let me know if I start to wear you all out answering questions.

KK

(15-May-2017, 09:21 AM)fftunes Wrote: On second read... is the FC power supply somewhat protected by low-esr caps or similar? Because electrical noise upsetting the gyro could eat away a lot of power and efficiency.

My friend had this problem once on a new build which didn't deliver half the power it was supposed to have. We could hear a high-frequency hum coming from it, but on your large build w/ large heavy props, something like this might be less noticeable.

FF, in reply to your post quoted above, I paid particular attention to my throttle position throughout the entire 4 minute flight today and I could detect no real change in throttle position or anything that would indicate that the batteries were sagging.

Even after landing I tried two more takeoffs and both times the quad lifted on much the same throttle setting.

So I think battery sag can be ruled out.

(08-May-2017, 02:13 AM)unseen Wrote: The slow fly props do have a much greater surface area than other shapes which would explain the significant increase in thrust.

It's a shame that static thrust tests can be so misleading though. As soon as you actually start moving and the propeller unloads, actual thrust is no longer the same as static thrust. I always knock off 30% to be on the safe side. And of course, while it's interesting to know what you can expect at maximum, the thrust at hover throttle is even more interesting.

Unseen, I must say I am still struggling to come to grips with this lack of power.

With regards to your comment above if the quad is pinned to the ground by the 6kg AUW then there is no forward movement and in theory, or at least the way I see it, thrust should equal 4 x 2.1kg at that instant. Yes I agree that once forward movement has started thrust will drop. But at the moment 4kg pins the quad to the ground, which is 1kg per motor. It just does not make sense.

Is there a possibility that my throttle range is not set correctly. According to Betaflight I have set the pulse width to the optimum pulse width range but I have never set it up using the joystick commands. Would this make a difference?

I just find this lack of a data log so annoying. I need some hard data on voltage current, RPM etc. I am not used to working like this.